Azo dye



Patented Mar. 9, 1926.

UNITED STATES PATENT oarce.

JOSEF HALLER, OF LEVERKUSEN, GERMANY, ASSI IGNOR T FARBENFABRIKEN VORM.

FRIEDR. BAYER AND 00., OF LEVERKUSEN, NEAR COLOGNE-ON-THE-RHINE, GER- MANY.

AZO DYE.

No Drawing m-xylidin.

I have found that the azo dyestuifs which are obtained by coupling diazotized asymmetrical m-xylidin compounds with 2-3 hydroxynaphthoic-acid arylids in which the aryl radicle is an asymmetrical m-xylidin compound have a distinctive superiority over similardyestufi's such as obtained'by coupling aromatic diazo compounds in gen oral and diazotized m-xylidin in particular with the 2-3-hydroxynaphthoic acid anilid.

My new products are distinguished by fuller, clearer shades, with particular improved :fastness to light and kier boiling when'produced on vegetable fibres. They are obtained 2 by diazotizing asymmetrical m-xylidin compounds, as for instance 1-3dimethyl-.4- aminobenzene, or' 1-3-dimethyl-4-amino-6- nitrobenzene and coupling with 2-8-hydroxynaphthoic-acid-asymmetrical m-xylidid compounds." When this operation is produced on vegetable fibres, the latter become dyed a deep, clear red shade, of excellent fastness ,Hto light and kier boiling. In substance my new dyestuffs are deep red powders, practicallv insoluble in water, soluble in concentrated sulfuric acid with a violet color. By reduction with e. g. zinc and hydrochloric 1 acid they yield an asymmetrical m-xylidin compound and an amino-2-3-hydroxynaph-.

40 thoic-asymmetrical-m-xy1idid. I

To further illustrate my invention the following example is given: j 10 gr. 2 3-hydroxy-naphtho'ic acid-asymmetrical-'m-xylidid, are dissolved-"in 1 litre water containing 15 cc. caustic soda 3i BI and 10 cc. Turkey, redloil, *A cotton hank is impregnated-with this" solution and squeezed out. I

'A diazo solution is then pre aredby dissolving 2.5 gr. f 1-3-dimethy -4=eaminobenzene in 400 cc. water containing 7 cc./concen trated hydrochloric acid. The spl ution is Application filed November 7, 1925. Serial No. 67,655;

cooled by the addition of ice and diazotized with 14 cc. of a 10% sodium nitrite solution.

' Sodium acetate is added-to make the reaction mlxture weaklyorganic.acid. The impreg nated cotton hank is now worked in this diazo solution for '20 minutes, squeezed, rinsed and washed in a soap solution. The cotton is then dyed a full bluish-red shade of excellent fastness to light and kierboiling. The dyestufi' recipita ted on the fibre has most probably t 'e formula 7 If a solution of 1-3-diinethy1-4-diazo-ben- 1-amino-2-hydroxy-3-naphthoic acid-asymmetrical-m-xyl-idid.

'The diazo compound from 6-nitro-4-amino-l-3-dimethylbenzene coupled with the 2-3 hydroxynaphthoic arylid, produced from be 6-nitro-4-amino-1-3-dimethylbenzene, produces on the fibre a more yellowish-red shade of the same excellent fastness'.

I claim:

1. As new products a'zo dyestufi's of the general formula v I P'mmdattachedin position 4 to the oombin= ing nitrogen atoms, which are deep red 0w-- ders, practically insoluble in water, solub e in concentratedsulfuric acid with violet color and yielding by reduction a l-amino-Q-hy- 'droxy-3-naphthoic aeid-asymmetrical-mxylidid compound and an asymmetricaLmxylidin compound.

2. As a new product the azo dyestufi having most; probably the formula which is a deep red powder, practically in- I soluble in water, soluble in concentrated sulfuric acid with a violet color and yielding by reduction asymmetrical-m-xylidin and 1-' amino-2-hydroxy-3-naphthoic acid-asymmetrical-m-ixylidid.

3. As new products vegetable fibres dyeda deep red shade, exceedingly fast-to light and kier boiling, with azo dyestuffs of the general formula in which R is a 1-3-dime thylbenzene' com-- pound attached in position 4 to the combining nitrogen atom,

fiAsnew products cotton'fibres dyed dee -r'ed shades exceedingly fast to light an kier boiling with the azo dyestufl of v the probable formula In hand;

y "JOSEF HALLEB. 

